Grease-cup plug



M. P. McLAUGHLI N. I

GREASE CUP PLUG.

APPLICATION FILED MAR. 25 1922.

lASCAEiBQ Patented Sept; 26, 1922..

' sue inwa I movement Patented Sept. 265, i922.

T" we it re atS MILI'ON P. MOLA'JGHLTN, OF WAKEFIELD,'IVIASSACHUSETTS,ASSIGNOR OF ONE-THIRD TO FRANK F. GOGGEN, 0F SQ'MERVILLE, MASSACHUSETTS,AND ONE-THIRD TO B. P. XVHITCHER, 0F MELROSE, MASSACHUSETTS.

GREASE-CUP PLUG.

Application filed March 25, 1922. Serial No. 546,600.

To all whom it may concern:

Be it known that I, MILTON P. MOLAUGH- LIN, a citizen of the UnitedStates, residing at /Vakefield, in the county of Middlesex and State ofMassachusetts, have invented new and useful Improvements in Grease- CupPlugs, of which the following is a specification. I i

This invention relates to plugs employed to confine a lubricant, andparticularly a relatively hard grease, in a grease cup carried by amoving part of a machine, such as a connecting-rod, or other partssubjected to vibration. A plug of this character is detachably securedto the rease cup by a screw-thread connection therewith. When the cup iscarried by a part, such as a connecting-rod, connecting the drivingwheels of a locomotive, the plug is often accidentally disengaged fromthe cup by the movements of the cup.

It is the object of my invention to provide simple and effective meansfor locking the plug to the grease cup in such manner as to preventliability of accidental displacement of the plug.

The invention is embodied in the improvements which I will now proceedto describe and claim.

01": the accompanying drawings forming a part of this specification,-

Figure 1 is a side view of a plug embodying the invention, showing thelocking dog projected.

' Figure 2 is a similar view, showing the locking dog released.

Figure 3 is a section on line 3'3 of Figure 1.

Figure 4 is a perspective view of the plun ger.

F igure 5 is an. end view of the, plunger looking toward the inner end.I

Figure 6 is a sectional view, showing the plug. adjusted as shown byFigure 1.

F igure 7 is a sectional view, showing the plug adjusted'as shown byFigure 2. k

Figure 8 is a perspective view of the lock ing dog.

F igure-9 showsthe plug on a considerably reduced scale, and a portionof a connecting-rod having a grease cup with which the plug is engaged.

Figure 10 is a sectional view, showing a modification.

' Agrease-cup plug 12 embodying my in- (611131011 1s externally threadedfor engagement with the internal thread of a greasecup or cavity, suchfor example, as a cup 13 in a locomotive connecting-rod 14c, andisprovided with a lateral guiding orifice 15,

intersecting a portion of the external screw thread. A locking-dog 16 ismovable in said orifice, and is composed of a material such as brass,adapted to be indented by said in- Y gagement and permit the'unscrewingof the plug.

The preferred embodiment ofthe invention shown by Figures 1 to 9,inclusive, includes means acting automatically to normally hold thedog-projected. into locking engagement with the cup thread, said meansbeing operable to release the dog,

In this embodiment of the invention, the plug 12 is provided with, acavity 18, open atthe outer end of the plug, and closed at the innerend, as shownby Figures 6 and 7, the guiding orifice 15 being a slotopening into the cavity. The dog 16 is formed to project partly into thecavity 18, and is provided with an ear 19, arranged to bear on the wallofjthe cavity and limitthe outward movement of the dog.

20 represents a plunger having a sliding fit in the cavity 18, andnormally pressed outward and yieldingly held in the position shown byFigures 1, 3, 6 and 9, by-a spring 21., interposed between the closedinner end of the plug and the bottom ofa socket 22 inthe plunger. Oneside of the-plunger has a recess 23, provided with an inclined faceportion 2 1, which is formedto bear on the correspondingly inclined backof the dog 16. p

The plunger is provided with a pin or stud 2 F, projecting from one sideof the plunger into an o ifice 25 in the plug. Said orifice has acam-shaped wall portion 25", the purpose of which will presently appear.The spring 21 normally holds the pin 2% against the outer side of theorifice 25, as shown by Figures 1 and 3, the plunger being, therefore,normally held in a raised position by the spring. The arrangement issuch that when the plunger is raised, its inclined face 2% acts on thedog ldto force the latterout ward to its internal thread-engaging position, shown by'lfigures 1 and 6. l hen the plunger is pressed inward,the position of the inclined face at is so changed that the dog isreleased from its threadengaging position, and is free to move inwardlyto the inoperative position shown by Figures 2 and 7.

The plunger 20 has a head 27, formed to be engaged by a wrench. When theplunger is raised by the spring the pin an is so related to thecam-shaped portion 25 that a partial rotation of the plunger in thedirection of the arrow m (Figure 1), will cause an inward movement ofthe plunger, the pin 24. being guided by the cam-shaped portion until itreaches the position shown by ure 2'. The movement thus imparted to theplunger releases the dog 16 from its operative position. A continuationof the turning movement. of the plunger, after the pin reaches theposition shown by Figure 2, causes the pin to turn the plug in the samedirection, the plunger and pin, therefore, constituting means forscrewing the plug into the grease-cup 13. The dog remains re leased fromits operative position while the plunger is being turned. When the forcewhich turned the plunger is removed, the

spring 21 forces the plunger outward, so

that the dog is forced to its operative or looking position, by thespring acting through the plunger, the spring being suitably stiti toenable it to press the dog firmly against the internal thread of thegrease cup, and prevent rotationof the plug, until the plunger ispressed inward and releases the dog.

l/Vhen the cup 13 is charged with grease, the plug may be screwed intothe cup to force grease to the bearing, by a wrench applied to the head27, the dog being released by this operation. l Vhen the wrench isremoved, the spring forces the plunger outward, so that the plug isautomatically locked by the dog.

The plunger is provided with a recess 30, beside the inclined face 24,the object of this recess being to facilitate theassemblage of theparts. The dog is inserted in the guiding slot 15, and held with its ear19 bearing on the internal surface of the plug. The plunger is theninserted in the plug, the re cess 30 being in alinement with the dog, sothat the back of the dog enters the recess. The plunger is then given apartial rotation, to move the inclined face 24 into contact with theback of the dog.

Figure 10 shows an embodiment of the invention in which the dog is notmoved auto matically to its locking position. In said embodiment 31represents the plug provided with an external screw-thread, adapted toengage an internal thread in a grease cup. The plug is provided abovethe thread with a wrench-engaging head 32, and is also provided with alongitudinal tapped orifice 33, and with a plurality of lateral guideorifices 3%, extending outwardly from the longitudinal orifice andintersecting portions of the external thread. "With the internal threadof the longitudinal orifice 33 T engage a threaded rod 35, which isprovided with a conical portion 36, between the lateral orifices 34.. Insaid lateral orifices are loosely inserted locking-dogs 37, of brass, orother like material, the inner ends of which contact with the conicalportion 36. Said dogs having substantially flat outer end faces adaptedto be indented by the portions of the internal thread with which itcontacts. The arrangement is such that inward endwise movement of therod 35 causes the conical portion 36 to simultaneously project thelocking-dogs 37 into locking engagement with the internal thread of agrease cup with which the plug is engaged, the length of thelocking-dogs being such that when the rod 35 is raised, the locking-dogsare released from pressure on the internal screwthread of the greasecup.

The subject-matter of Figure 10 is shown in my pending application,filed June 14, 1921, Serial No. 477,425, of which this application is acontinuation in part.

I claim:

1. A grease-cup plug externally threaded for engagement with theinternal thread of a grease cup, and provided with a lateral guidingorifice intersecting a portion of the screw-thread, a locking-dogmovable in said orifice, and composed of a material adapted to beindented by said internal thread without mutilating the latter, said doghaving a substantially flat outer end face, and means for forcing thedog outward tocause the indentation of said end face by the saidinternal thread, so that the dog has a look ing engagement with theinternal thread, said means being adapted to release the dog from saidlocking engagement.

2. A grease-cup plug externally threaded for engagement with theinternal thread of a grease cup, and provided with a lateral guidingorifice intersecting a portionof the screw-thread, a locking-dog movablein said orifice, and composed of a material adapted to be indented bysaid internal thread without mutilating the latter, said dog having asubstantially fiat outer end face, and automatic means normally forcingthe dog outward to cause the indentation of said' end face by the saidinternal thread, so that the dog has a locking engagement with saidthread, said means being operable to release the dog from said lockingengagement.

3. A grease-cup plug externally threaded and provided with a cavitywhich is open at the outer end, and with a-lateral guiding orificeintersecting a portion of the screw thread, a locking-clog movable insaid orifice,

and projecting into the cavity, a plunger movable in said cavity, aspring exerting an outward pressure on the plunger, the plun ger beingprovided with an inclined bearing face, whereby the dog is projected toa looking position, when the plunger is moved outward by the spring, thedog being releasable from its locking position by an inward movement ofthe plunger.

4. A grease-cup plug externally threaded and provided with a cavitywhich is open at the outer end, and with a lateral guiding orificeintersecting a portion .of the screw thread, a locking-dog movable insaid orifice, and projecting into the cavity, a plunger movable in saidcavity, a spring exerting anoutward pressure on the plunger, the plungerbeing provided with an inclined bearmg face, whereby the dog isprojected to a locking position, when the plunger is moved outward bythe spring, the dog being releasable from its locking position by an inward movement of the plunger, the plunger being provided with alaterally projecting pin, and the plug with a pin-receiving orificeformed to cooperate with the pin in impart- 7 ing rotary movement fromthe plunger to the plug, the plunger being formed at its outer end to beengaged by a tool.

5. A grease-cup plug substantially as specified by claim 4, the saidorifice being provided with a cam-shaped wall portion, formed tocooperate with said pin in moving the plunger inward to release the dogwhen the plunger is turned to screw the plug into a grease cup.

In testimony whereof I have aifixed my signature.

MILTON P. MOLAUGHLIN.

